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| United States Patent |
5,755,537
|
|
Lubbering
|
May 26, 1998
|
Portable precision drill
Abstract
A drill incorporates an axial feed drive, measuring system for determining
the feed distance, a computer for controlling the axial feed drive as a
function of the axial feed distance and a rotary drive for driving the
tool spindle with pre-established on-load speed or pre-established torque
or load moment. The flow or feed of cutting lubricant to the tool is
controlled as a function of the pre-established on-load speed or the
combination of the pre-established load moment, and the axial feed.
| Inventors:
|
Lubbering; Johannes (Herzebrock, DE)
|
| Assignee:
|
Johannes Lubbering AG (Erlenstrasse, CH)
|
| Appl. No.:
|
648177 |
| Filed:
|
July 16, 1996 |
| PCT Filed:
|
November 14, 1994
|
| PCT NO:
|
PCT/EP94/03771
|
| 371 Date:
|
July 16, 1996
|
| 102(e) Date:
|
July 16, 1996
|
| PCT PUB.NO.:
|
WO95/14550 |
| PCT PUB. Date:
|
June 1, 1995 |
Foreign Application Priority Data
| Nov 23, 1993[DE] | 43 39 770.0 |
| Current U.S. Class: |
408/3; 408/8; 408/10; 408/16; 408/56; 408/57; 408/137 |
| Intern'l Class: |
B23B 039/08; B23Q 015/12; B23Q 015/24; B23Q 011/10 |
| Field of Search: |
408/3,8-13,16,56,57,137
|
References Cited
U.S. Patent Documents
| 3859001 | Jan., 1975 | Hoddinott et al. | 408/10.
|
| 4076442 | Feb., 1978 | Cox, Jr. et al. | 408/8.
|
| 4514123 | Apr., 1985 | Johnstone et al. | 408/8.
|
| 4688970 | Aug., 1987 | Eckman | 408/9.
|
| 5123789 | Jun., 1992 | Ohtani et al. | 408/16.
|
| 5613810 | Mar., 1997 | Bureller | 408/3.
|
| Foreign Patent Documents |
| 6-023612 | Feb., 1994 | JP | 408/16.
|
| 2218268 | Nov., 1989 | GB.
| |
Primary Examiner: Bishop; Steven C.
Attorney, Agent or Firm: Baxley, Esq.; Charles E.
Claims
I claim:
1. A portable drill for performing drill operations on a workpiece
comprising:
a frame;
a tool spindle displaceably mounted on said frame;
feed drive means mounted on said frame and connected to said tool spindle
for displacement of said tool spindle;
rotary drive means for rotation of said tool spindle;
measurement system means mounted on said frame;
depth sensor means mounted on said measurement system means for detecting
feed distance of said tool spindle;
computer means mounted on said frame for regulating said feed drive means
with said computer means connected to said rotary drive means and to said
feed drive means for the purpose of regulating said feed drive means as a
function of decrease in speed of said rotary drive means during operation
with a decrease in said feed drive speed corresponding to a decrease in
said rotary drive speed;
axially displaceable feeler nose means disposed generally para-axially with
respect to said tool spindle for the purpose of making contact with said
workpiece for detecting a reference portion of said workpiece; and
lubricant feeding means mounted on said frame for feeding lubricant as a
function of said rotary drive speed.
2. A drill according to claim 1, further comprising:
tool spindle mounting means for mounting said tool spindle in said frame
with said tool spindle mounting means comprising:
a rotatable bushing connected to said rotary drive means;
a groove member of said tool spindle with said groove member having a
plurality of generally para-axial grooves;
a groove member of said rotary drive means, with said groove member having
a plurality of generally para-axial grooves; and
a plurality of balls, with said balls engaging said groove member of said
rotary drive means and said tool spindle thereby forming a driving
connection.
3. A drill according to claim 2, wherein said tool spindle mounting means
comprises:
a first bushing and a second bushing, with said first bushing spaced apart
from said second bushing and with said tool spindle having a first end and
a second end and with said tool spindle capable of an extended position
and a retracted position, with said first and said second bushing spaced
apart to support said tool spindle when said tool spindle is in said
extended position and in said retracted position.
4. A drill according to claim 1, wherein said rotary drive means comprises
a motor, with said motor disposed generally paraxially relative to said
tool spindle mounting means and disposed generally proximate to said tool
spindle mounting means.
5. A drill according to claim 1, further comprising:
a speed indicator disposed on said rotary drive means.
6. A drill according to claim 1, wherein said feed drive means comprises:
a rotatably mounted threaded spindle;
a nut, with said nut threaded onto said threaded spindle with said, nut
fixed in the direction of rotation and displaceable in axial direction
along said threaded spindle, with said nut connected to said tool spindle.
7. A drill according to claim 6, wherein said tool spindle comprises:
a hollow section, with said threaded spindle projecting into said hollow
section and with said nut axially disposed on said tool spindle.
8. A drill according to claim 6, further comprising:
a feed motor, with said feed motor connected to said threaded spindle; and
incremental rotary transducer means with said incremented rotary transducer
means connected to said threaded spindle for measurement of feed distance
of said tool spindle.
9. A drill according to claim 8, wherein said feed motor and said
incremental rotary transducer means are disposed on said tool spindle
generally diametrically opposite said rotary drive means.
10. A drill according to claim 1, comprising:
an axial channel portion formed in said tool holder, and an axial channel
portion formed in said tool spindle with said channel portion in said tool
holder communicating with said channel portions in said tool spindle for
feeding of lubricant;
said lubricant feed means mounted on said tool spindle and communicating
with said channel portion in said tool spindle for feeding lubricant
through said channel portion in said tool spindle and through said channel
portion in said tool holder.
11. A drill according to claim 10, further comprising:
a hollow tool mounted in said tool holder;
a hollow lance, with said hollow tool having a plurality of transverse hole
portions, and with said hollow lance disposed projecting into said hollow
tool and projecting into said axial channel portion formed in said tool
spindle.
12. A drill according to claim 11, wherein said hollow tool has a withdrawn
position and an extended position and in which said lance is of such a
length so that when said hollow tool is in said withdrawn position, said
transverse hole portions are blocked, and as said hollow tool advances
toward said extended position, said transverse hole portions gradually
open.
13. A drill according to claim 11, further comprising:
said lubricant feed means disposed to feed lubricant into said hollow
lance.
14. A drill according to claim 10, in which said lubricant feed means is
disposed to feed lubricant into said axial channel portion in said tool
spindle intermittently with air bubbles introduced between portions of
lubricant.
15. A drill according to claim 11, wherein said lubricant feed means is
disposed to introduce lubricant into said hollow lance intermittently with
air bubbles introduced between portions of lubricant.
16. A drill according to claim 10, further comprising:
said computer means connected to said lubricant feed means, with said
computer means capable of a variable pulse-pause ratio operation defined
as directing the flow of only lubricant or lubricant with air bubbles into
said hollow lance during pulse operation and directing the flow of only
air into said hollow lance during pause operation.
17. A portable drill for performing drill operations on a workpiece
comprising:
a frame;
a tool spindle displaceably mounted on said frame;
feed drive means mounted on said frame and connected to said tool spindle
for displacement of said tool spindle;
rotary drive means for rotation of said tool spindle;
measurement system means mounted on said frame;
depth sensor means mounted on said measurement system means for detecting
feed distance of said tool spindle;
computer means mounted on said frame for regulating said feed drive means,
with said computer means connected to said rotary drive means and to said
feed drive means for the purpose of regulating said feed drive means as a
function of decrease in speed of said rotary drive means during operation,
with a decrease in said feed drive speed corresponding to a decrease in
said rotary drive speed;
axially displaceable feeler nose means disposed generally para-axially with
respect to said tool spindle for the purpose of making contact with said
workpiece for detecting a reference portion of said workpiece; and
lubricant feeding means mounted on said frame for feeding lubricant as a
function of load moment and feed distance.
18. A drill according to claim 1, wherein said rotary drive means comprises
motor means and further comprising:
speed indicator means disposed on said motor means.
19. A drill according to claim 11, further comprising:
said lubricant feed means disposed to feed lubricant into said axial
channel portion in said tool spindle.
20. A drill according to claim 11 further comprising:
spring means, with said spring means disposed to urge said lance in a feed
direction relative to said tool.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to the field of portable drills and
more particularly to a portable drill for fastening onto the drilling
location of large workpieces for precision drilling work by means of a
tool through which a liquid lubricant is conducted to the tool cutting
edges, having a tool spindle which is displaceable in its axial direction
by a separate drive with a tool holder, through which the lubricant is fed
and a drive for the rotating axial advance of the tool spindle.
Such a drill is used in all precision drilling work in which the workpieces
are of such a size that they cannot be drilled on stationary drilling
machines. A preferred field of use of such drills is in the aeronautical
industry in order, for instance, to produce, in airplane construction,
those holes which are to be provided for the attachment between the
fuselage and the wings. The drill in question is either arranged fixed on
an auxiliary device or, in variable use, is employed in locking bushings,
in templates, or in similar holding devices. Particularly exact precision
of machining on the part of such drills is required upon the reaming of
previously produced holes, for which purpose conical reaming tools having
a conical shoulder are used.
THE PRIOR ART
The prior art related to drills including the drill shown in U.S. Pat. No.
4,688,970. U.S. Pat. No. 4,688,970 shows a drill which has a drive motor
which assures the feeding of the work spindle towards the workpiece and
back from it. Sensors are seated on the tool spindle in order to check
that the drill complies with the working data determined over the working
path, and in particular reaches the predetermined depth of drilling with
the tool in order then to be withdrawn again from the borehole. Auxiliary
means for detecting the top side of the workpiece in order to be able to
determine the depth of penetration of the tool into the workpiece from
that point are not present in the known apparatus. This is true also of
other previously known drills which have only a single drive, both for the
rotating of the tool spindle and for the feeding thereof. In these
machines, when they are under load, the feed decreases also simultaneously
with the speed of rotation; on the other hand, the basic speed of rotation
upon idle travel must not be selected too high, so that the idle distances
here can be moved over only with relatively low speed.
One essential disadvantage of the known drill machine lies in its high
consumption of lubricant, this being a drilling liquid of high quality
which is very expensive. The amount of lubricant fed is established
empirically based on an estimate of the drilling or reaming process,
regardless of the length of engagement of the tool. The drilling or
reaming tools used for precision holes have, distributed over their entire
cutting length, radial holes which are supplied from a central feed
channel. Since the cutting agent is fed continuously in the known
embodiments, overdosing takes place as long as the tool is not in
engagement over its entire cutting length. Also upon the pulling back of
the tool without drilling or reaming work, the lubricant continues to be
fed, unutilized, in the known drills. As a whole, therefore, the
consumption of lubricant is about ten times as high as required from a
purely theoretical standpoint for the actual cutting process.
The known drills also have disadvantages structurally. The tool spindle is
mounted at the rear of the machine in an axial conveying thread which is
necessary for the feed. Despite additional supporting of the spindle in
the front region of the machine, movements of radial deflection are
unavoidable, which impairs the accuracy of the drilling. Furthermore, the
machining distance, the drilling depth, cannot be precisely determined in
the known machines since for this, a depth stop is required which is
placed on the wall of the material surrounding the hole in question and
which indicates that the drilling depth has been reached in the manner
that the tool spindle comes against a corresponding stop on the inner end
of the depth stop, as a result of which the feed is turned off.
Finally, the known drilling machines are complicated to adjust. Each tool
is subject to wear and must be regularly replaced, must have its working
stroke readjusted empirically in a testing shop. This is done by turning
the tool spindles together with their aforementioned conveyor screw in and
out of the corresponding threaded bushing for the feed, for which a
partial assembling of the machine, at least in the front region of the
mechanical drive, is necessary in order to be able axially to displace a
setting or stop nut on the conveyor thread of the tool spindle which
strikes against the inner end of the depth stop at the end of the working
stroke.
OBJECT AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a portable precision
drill which operates with a high degree of precision and is economical in
the consumption of lubricant.
The foregoing and other objects and advantages of the present invention
will appear more clearly hereinafter.
In accordance with the present invention there is provided a portable
precision drill which incorporates a measuring system for determining the
feed distance, a computer for controlling the feed drive as a function of
the axial feed distance and a rotary drive for driving the tool spindle
with pre-established on-load speed or pre-established torque or load
moment. The flow or feed of lubricant to the tool is controlled as a
function of the pre-established on-load speed or the combination of the
pre-established load moment, and the feed.
It is essential for the invention to be able to operate the motor for the
rotary drive always at full load either with the highest possible speed of
rotation or with the greatest possible torque. It is optimal to adapt
these operating parameters to the drilling output and therefore to work
with the greatest possible drilling output. The separate feed drive, the
feed speed of which is independent of the speed of rotation of the rotary
drive, can be operated with a high feed speed at the start of the
machining cycle when the tool is not yet in engagement with the material
or only slightly in engagement with it, after which, as a function of the
decrease in the speed of rotation of the rotary drive motor, the feed
speed is reduced in accordance with a pre-established function. This
control or regulation can also be effected as a function of the torque,
which is dependent on the specific operating conditions, such as, for
instance, the characteristics of the material. Suitable sensors for speed
of rotation and/or torque are installed in the rotary drive and the
suitable desired value to be set in each case can be derived in suitable
manner so as to introduce it into the computer and evaluate it there.
As a result of the evaluation in the computer, the feed of the liquid
lubricant is also controlled so that the smallest possible amount of
lubricant is used. Thus, at the start of the machining process as long as
the tool is only slightly in engagement with the material, only a small
amount of lubricant is fed and the addition of lubricant is increased with
increasing machining engagement.
The separation of rotary drive from feed drive affords the further
advantage that towards the end of the drilling or reaming process, one can
operate with only a slight feed, which greatly increases the precision of
the machining upon full engagement of the tool. For this, there is
necessary an exact determination of the instantaneous position of the
tool, for which the measurement system for determining the feed distance
serves. As a function of a reference point, the position at the time of
the tool spindle in axial direction is determined, for which a so-called
absolute distance measurement is provided. To this distance measurement
system there is connected a sensor system which is placed on the surface
of the workpiece to be machined in the direct vicinity of the tool
engagement and establishes a reference point. Furthermore, the data of the
specific tool employed can be entered into the computer of the apparatus
and in this way the working stroke which enters into consideration in each
case can be fixed so that up to the end of the fine drilling one can work
precisely with the slight feed.
The measurement system for the feed distance makes it possible furthermore
to operate with the highest possible feed of the separately developed feed
drive until engagement of the tool, which considerably shortens the entire
machining time so that the machining cycle requires only about one-third
as much time as traditional machines.
The measurement system for determination of the feed distance makes it
possible furthermore to establish the maximum wear of the tool in the
manner that, for instance, comparative values are stored in the computer
and the deviation from these reference values determined. Furthermore, the
determination of the feed or working distance of the tool creates the
possibility of temporarily withdrawing the tool even during the machining
process so that, fort instance, problematic chips can be removed from the
borehole.
The computer of the drilling machine serves for the evaluating of all data
and for controlling the functions and operations. Furthermore, there is
provided on the drilling machine a memory chip which bears the individual
data of the machine and of the tool used, which are introduced upon
overhaul or upon new use of the apparatus. At the beginning of each use,
these data are interrogated and fed to the computer, evaluated in it so
that the working distance and the lubricant feed can be determined. In
this way, the maintenance data of the drill and of the tool can be
pre-established so that the maximum wear is not exceeded. Via a data
interface, the drill can be linked with another drill and/or a central
computer so as to permit of central monitoring and evaluation of the
operating data of the machines and tools.
DESCRIPTION OF THE DRAWINGS
Other important objects and advantages of the invention will be apparent
from the following detailed description, taken in connection with the
accompanying drawings, in which:
FIG. 1 is a diagrammatic view, partially in longitudinal section, of a
portable precision drill made in accordance with the present invention;
FIG. 2 is a view of the front region of the drill of FIG. 1, drawn to an
enlarged scale;
FIG. 3 is a view of the rear region of the drill of FIG. 1, drawn to an
enlarged scale; and
FIG. 4 is a diagrammatic view of the feeding of lubricant to the tool of
the drill of FIG. 1, showing three different positions of the tool.
DETAILED DESCRIPTION OF THE INVENTION
With reference to the drawings, wherein like reference numbers designate
like or corresponding parts throughout, there is shown in FIGS. 1-3 a
portable precision drill 100 made in accordance with the present invention
which includes a tool spindle 1 mounted in a machine frame 102. The tool
spindle 1 has a tool holder 2 at its front end. In it there is inserted a
drilling or reaming tool 3 which has an axial channel 4 for the feeding of
a lubricant to the tool cutting edges. Communicating the axial channel 4
there are transverse holes 5 which are arranged over the entire length of
the cutting region of the tool 3. The feeding of the lubricant to the tool
3 takes place through the tool spindle 1 which, for this purpose, has an
axial channel 6 which extends further in axial direction up to the rear
end of the drill 100.
In order to effect the advance of the tool 3 upon the machining process,
the tool spindle 1 is mounted for displacement in its axial direction. For
this there are provided two bushings 7 which are rotatably supported in
the machine frame 102 and have within them para-axial longitudinal grooves
in which balls 8 are arranged. Balls 8 engage in para-axial longitudinal
grooves 9 in the tool spindle 1 so that the tool spindle 1 can turn with
the rotatably mounted bushings 7 and, independently thereof, be pushed in
axial direction with respect to the bushings 7. In order to avoid radial
play of the tool spindle 1 as far as possible, the bushings 7 are arranged
at the greatest possible distance from each other. Thus, in the withdrawn
end position of the tool spindle 1, the tool holder 2 lies directly at the
outlet end of the front bushing 7, referred to the direction of feed. In
the same way, the rear end of the tool spindle 1 in the advanced end
position lies directly at the entrance end of the rear bushing 7.
The tool spindle 1 is placed in rotation by a rotary drive 15 which
includes a gear rim 10 which is seated on the outer circumferential side
of the front bushing 7. Via a toothed gearing 11 this gear rim 10 on the
bushing 7 is in engagement with an output gear 12 of a motor 13 which is
arranged para-axial to the tool spindle 1. The motor 13 can be a
compressed-air motor which is of relatively high power but of small size.
The motor 13 is operated under load with a predetermined speed of rotation
so that the tool spindle 1 and thus the tool 3 are also maintained at a
given speed of rotation. The motor 13 can thus be operated in the most
favorable power range, in which connection it itself need not be further
controlled or regulated.
Rather, merely the speed of rotation of the rotary drive 15 is detected,
for which purpose a speed measuring device 14 is seated at a suitable
place in the rotary drive 15. The speed-dependent signal of the speed
measuring device 14 is introduced into a computer 104 which, on the basis
thereof, determines the feed speed for the tool spindle 1. The computer
104 is illustrated schematically by the rectangle 106 in FIG. 1. The
computer 104 is connected to the lubricant feed device 31 and to the feed
drive 25 by conventional connections. As long as the speed of rotation of
the rotary drive 15 for instance at the start of a machine cycle has still
not dropped to the optimal on-load speed, one can operate with an
increased feed, which is completely uncoupled mechanically from the speed
of rotation of the rotary drive 15. Instead of a compressed-air motor
there can also be used as motor 13 an electric motor which, in addition,
affords the possibility of being operated with a predetermined load
moment, which can be determined via the current consumption of the
electric motor.
The computer 104 controls a feed drive 25 in the manner that upon the idle
travel over which the tool 3 is not in engagement with the material, one
can operate with maximum speed of feed, which is true both for the start
of an operating cycle and for the extracting of the tool. Furthermore, the
feed drive 25 is so regulated that optimal cutting conditions with due
consideration of the most favorable on-load speed of the motor 13 are
maintained. In this connection furthermore, a distinction is made between
normal machining and precision machining, high speed of rotation and low
feed being used in the latter case.
As shown in FIGS. 1 and 3, the feed drive 25 comprises a rotatably mounted
threaded spindle 17 which is not displaceable in axial direction. The
threaded spindle 17 engages into a hollow section 16 in the region of the
rear end of the tool spindle 1. On the threaded spindle 17 a nut 18 is
arranged in such a manner that it is fixed in direction of rotation, this
being assured by a carriage 20 which is guided on a para-axial guide 21 on
the machine frame. This guide 21 extends over a region of axial
displacement of the nut 18 which coincides with the total feed distance of
the tool spindle 1. The rear end of the hollow section 16 of the tool
spindle 1 is rotatably supported in the nut 18, but is firmly attached in
axial direction with the displaceable nut 18. By means of rotary balls 19
which engage both in the threaded spindle 17 and in a mating thread of the
nut 18, the axial displacement of the nut 18 and thus the feed of the tool
spindle 1 are effected upon rotation of the threaded spindle 17. The
rotary drive of the threaded spindle 17 is effected via a belt
transmission 22 by means of a feed motor 23, which can be a stepping
motor.
The belt drive 22 furthermore drives a measurement system 24 which consists
predominantly of an incremental rotary transducer. Via the signals
supplied by the rotary transducer, the feed distance of the tool spindle 1
can be precisely determined so that an absolute measurement of the
distance is possible. The measurement system 24 is connected in
corresponding manner with the computer 104 or the drill machine 100, so as
to control the feed of the tool 3 for the predeterminable idle distances
as well as the machining and precision machining distances via the feed
drive 25 and possibly readjust it as a function of the speed of rotation
of the tool spindle 1 which can be detected via the speed of rotation
measuring device 14.
As further shown in FIG. 1, the measurement system 24 can be supplemented
for the detection of the feed distance by means of a depth sensor which is
connected by a rod 29 to a feeler tube 27 which is arranged in a sleeve 26
which surrounds the tool 3 in its withdrawn end position. The feeler tube
27 also surrounds the tool 3 and has a feeler nose 28 which can be placed
on the material of the workpiece in question in the region of the edge of
the hole to be machined. Since the distance between the tool and the
feeler end of the feeler nose in its fully extended position is known, a
reference signal for the tool spacing in the initial position can be
determined via the feeler sensor 30 via the distance of indentation of the
seated feeler nose 28 when the drill is placed on a workpiece. In
particular, in this way it is possible to establish a zero point for the
control or regulating of the computer 104 in cooperation with the
measurement system 24.
From FIG. 1 it can furthermore be noted that the axial channel 6 for the
feeding of the lubricant to the tool 3 extends not only through the tool
spindle 1 but also through the threaded spindle 17 up to a lubricant feed
device 31 which is placed on the rear end of the drill 100. In the axial
channel 6 a lance 32 in the form of a small tube is present, as can be
noted in detail from FIG. 4. The lubricant is transported through this
lance 32 from the lubricant feed device 31 to the tool 3 in such a manner
that it emerges there through the corresponding transverse holes 5 which
adjoin the lubricant channel 4 of the tool 3 only when it is also actually
used. This is the case upon engagement by the tool 3 with the material of
workpiece but not upon the empty paths which the tool 3 has moved over at
the start of an operating cycle and upon the withdrawal from the hole
drilled. When the tool 3 is withdrawn, the lance 32 extends so far into
the lubricant channel 4 of the tool that all the transverse holes 5 are
closed. Over the first idle path which the tool must move over up to the
borehole, the lance 32 travels along so as to keep all the transverse
holes 5 closed, as previously. For this purpose, the lance 32 is held
displaceable by the distance "X" in axial direction in the lubricant feed
device 31, in which connection it is pressed by means of a rear spring 33
in the direction towards the tool holder 2 of the tool spindle 1. When the
lance 32 has reached in feed direction the end of the axial displacement
path, a relative movement takes place between the lance 32 and the tool 3
upon the further feeding of the tool 3, in the manner that, starting with
the front transverse hole 5, the transverse holes 5 are gradually
unblocked for the emergence of the lubricant. Upon the pulling out of the
tool 3, the transverse holes 5 are closed in the reverse sequence, and the
relative movement between the tool 3 and the lance 32 ends as soon as the
lance 32 is seated at the front end of the axial lubricating channel 4 of
the tool 3. Instead of this, there can also be provided a different
driving device 34 in order to effect the pushing back of the lance 32 into
the starting position.
The computer 104 of the drill 100 also controls the lubricant feed device
31 since the need for lubricant is not only dependent on the distance but
must also be adapted to the specific operating conditions, such as the
main machining process or the precision m machining. The lubricant feed
device 31 conveys the lubricant in portions into the lance 32, in which
connection air bubbles between the individual portions of lubricant are
forced into the lance 32. In this way, the lubricant is atomized upon
emergence from the transverse holes 5 of the tool 3, assuring a uniform
wetting of the cutting places. Furthermore, the lubricant feed device 31
can be operated in a variable pulse-pause ratio, in which case, for the
duration of the pulse, either only lubricant or portions of lubricant with
air bubbles are introduced into the lance 32, while for the duration of
the pauses, only air is introduced into the lance 32. In particular, in
this way one can avoid the possibility that a residual volume of lubricant
which is still present in the entire lubricant feed line is discharged out
of the transverse holes upon the pulling back of the tool 3.
The computer 104 performs an evaluation of all data and controls the
functions and operations of the drill 1. Furthermore, there is provided in
the computer 104 a memory chip which bears the individual data of the
drill machine 1 and of the tool 3 used, which are introduced upon overhaul
or upon new use of the apparatus 1. At the beginning of each use, these
data are interrogated and fed to the computer 104, evaluated in it so that
the working distance and the lubricant feed can be determined. In this
way, the maintenance data of the drill 1 and of the tool 3 can be
pre-established so that the maximum wear is not exceeded. Via a data
interface, the drill 1 can be linked with another drill 1 and/or a central
computer so as to permit of central monitoring and evaluation of the
operating data of the machines and tools 3.
The foregoing specific embodiments of the present invention as set forth in
the specification herein are for illustrative purposes only. Various
deviations and modifications can be made within the spirit and scope of
this invention, without departing from the main theme thereof.
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